Sohna Road pe site visit mein kya kya check karein?

Okay I'll be honest — I'm completely confused with site visits for my first home. Sohna Road pe Lion Infra Developers ka project dekhne gaya tha, but builder rep ne bas glossy brochure dikhaya. Main kya kya points check karta? Like, water pressure, cell network, ya aas paas ka noise level? My parents keep saying 'har cheez dhyan se dekho', but I don't even know what to ask. Negotiation bhi possible hai kya, ya prices fixed hote hain? Ab samajh nahi aa raha.